1. Field of the Invention
This invention relates to dumbbells and is more particularly concerned with dumbbells which are collapsible for storage and which can be expanded by introduction of fluid when required for use in exercising.
2. Description of the Prior Art
Dumbbells and barbells, which are collapsible for easy transportation and expandable, by introduction of fluids such as water and the like, when required for use, have been described previously.
Illustratively, Winer U.S. Pat. No. 3,231,270 describes a barbell which is collapsible for ease of transportation and which comprises two collapsible, spirally pleated fluid chambers each having a centrally disposed passage by means of which the fluid filled chambers can be securely mounted on either end of a metal bar. The latter can be comprised of several pieces which can be threadably connected to form a single bar of a desired length.
Bosko e al U.S. Pat. No. 3,334,899 describes a similar device which can be employed as a barbell or dumbbell depending upon the length of the bar employed. The device comprises two bulbs of rubber o plastic which can be filled with water or like fluid. The bulbs preferably have transparent walls so that decorative effects can be achieved by introducing flaked materials, miniature dolls and the like in suspension in the fluid employed for filling the bulbs. The bulbs are sealed with a plug and provided with female threaded sockets which engage male threads on the end of a hollow bar when the barbell or dumbbell is assembled.
Baker et al U.S. Pat. No. 3,781,007 also shows a device which can be employed as a dumbbell or barbell depending upon the length of the bar and the size of the attached collapsible fluid containers. In this instance the latter are suspended below opposite ends of the bar, using bearings which allow the bar to rotate when in use. The bar can be formed in sections which can be dismantled for ease of transportation.
Ionel U.S. Pat. No. 4,076,236 describes a dumbbell (hantel) comprising a handle on to each end of which can be mounted one or more hollow bodies each of which is fillable with fluid and is adapted to be attached threadably to the handle or a previously mounted hollow body. The weight of the barbell can thus be adjusted to a variety of levels thereby avoiding the need to have available and/or to transport a series of individual barbells of different weights. The device is readily disassembled for transportation and readily re-assembled when required for use.
The present invention is directed to a form of dumbbell which is collapsible when not in use but which does not require any assembling of components, other than introduction of fluid, prior to use and which is possessed of other advantages which will become apparent from the description which follows.